Removing obsolete include ChronoIO.h, instead include directly Accumulators.h
Spotted build warning for LHCb on lhcb-head (e.g. lhcb-gaudi-head/4225):
/dependencies/Gaudi/InstallArea/x86_64_v2-el9-gcc13-opt/include/Gaudi/Chrono/ChronoIO.h:14:4: warning: #warning "deprecated header file, not to be used" [-Wcpp]
14 | # warning "deprecated header file, not to be used"
| ^~~~~~~